“At all” means something like “anything more than zero” or “even a little bit.”
It’s often used in negatives:
I don’t eat pork at all. = I don’t eat pork – not even a little bit.
He doesn’t exercise at all. = He does NO exercise
The party was no fun at all. = There was zero fun, not even a little
I can’t sing at all. = I have zero singing talent
In questions, the person is inquiring about ANY activity, even small/infrequent:
Do you drive at all? = Do you drive – even a little bit / infrequently?
If you drive (even only a little bit / occasionally), then the answer is YES.
If you never drive, then the answer is NO.
Did he say anything at all? = Did he say anything, even just a tiny/short phrase?